Doctor Who Theory Reveals Ncuti Gatwa's Doctor Told 1 Huge Lie In Season 14, Episode 3

Warning: This article contains spoilers for Doctor Who season 14, episode 3, "Boom."

Summary The Doctor's lie in "Boom" hints at their emotional baggage and unique bond with Ruby Sunday in Doctor Who season 14.

Mundy's scan doesn't prove the Doctor's truthfulness, pointing to the possibility of deception in the episode.

Steven Moffat's era emphasized the Doctor's lies, making it plausible that the Doctor would deceive Mundy to protect Ruby.

A theory surrounding Doctor Who season 14, episode 3, “Boom” points to the idea that Ncuti Gatwa’s Doctor told one major lie. Doctor Who’s new season has started introducing Whovians to Ncuti Gatwa’s Fifteenth Doctor, the most recent version produced through the Doctor’s bi-generation in the Doctor Who 60th anniversary special, “The Giggle.” The newest Doctor has been shown dancing, singing, and being playful in a way most of their previous versions haven’t, setting them apart.

Despite having a unique personality from every Doctor in Doctor Who, the Fifteenth Doctor still holds the emotional baggage of their past regenerations and the anguish at learning their past was a lie. Both of these aspects of the character allow them to bond extremely closely with their newest companion, Ruby Sunday, due to their similarities. Based on one theory, the Fifteenth Doctor may have fallen back into one of the Doctor’s old habits – lying – in order to help save Ruby in Doctor Who’s season 14 episode “Boom.”

Related Doctor Who Season 14 Episode Guide Doctor Who season 14's eight episodes are brimming with important details, fun cameos, and major lore callbacks. Find everything you need here.

Doctor Who Theory: The Doctor Lied About What Would Happen If The Mine Blew Him Up

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The most confusing moment in Doctor Who season 14, episode 3, “Boom,” is the Doctor’s telling Mundy about killing half of the planet if the landmine exploded. While it would make sense that a Time Lord would interact with the bomb differently than a human, earlier in the episode, the Doctor tells Ruby Sunday earlier in the episode that they don’t want her to come near them when passing off the compressed body cylinder of John Francis Vater because she would be in range if the bomb exploded. These two statements directly contradict each other, leaving two big possibilities.

Even if they were okay with dying, the Doctor would never allow Ruby to die without putting up a fight in Doctor Who.

Firstly, the Doctor could have only realized the danger of the situation later in the episode when he started glowing, indicating that he was the bomb, instead of just activating it. However, they knew a lot about the make and model of the mine from the start, indicating that they would probably know how the bomb works. It wouldn’t come as a surprise to them that the landmine turns the person standing on it into the bomb. The second possibility is that the Doctor could have lied to one of the two women about the bomb’s explosion.

If the Doctor was going to lie to either of the two about the bomb, they would likely choose to lie to Mundy about the possibility. The Doctor is pretty open and frank with Ruby Sunday, making it confusing that they would lie to her about the danger of the bomb. It also seems probable that the Doctor would have told Ruby to take the TARDIS and go if they knew that she would likely die in a planet-wide explosion.

Related Who Is Ruby's Mother In Doctor Who? 10 Biggest Theories Doctor Who has introduced Millie Gibson as the Doctor's new companion, Ruby Sunday, and set up a thrilling mystery - who is her mother..?

Additionally, Mundy was the primary barrier to saving the Doctor and Ruby at the time of the Doctor’s statement. Even if they were okay with dying, the Doctor would never allow Ruby to die without putting up a fight in Doctor Who. This is the whole reason they didn’t Ruby to pass off the compressed body cylinder instead of tossing it. It isn’t out of the realm of possibility that the Doctor would lie to Mundy to ensure Ruby’s survival.

Mundy Flynn's Scan Wouldn't Have Shown The Explosion's Effects

The biggest thing pointing to the fact that the Doctor isn’t lying to Mundy in Doctor Who season 14, episode 3, “Boom,” is the fact that she scans the Doctor to see if they are lying to her about their identity and what will happen. The scan is never shown on screen, but she reacts as if it confirmed everything the Doctor said. There are two big problems with this proving that the Doctor is telling the truth about what will occur, both of which come back to the way that Mundy Flynn’s technology works.

Most recognizably, the Doctor already lies to Mundy in a provable way. They say that they are a Time Lord when explaining how immolation would impact them. The Doctor isn’t actually a Time Lord, though; they are the Timeless Child, which is an unknown species. Based on this lie, it’s likely that the machine only registered them as an unfamiliar species, not a Time Lord specifically.

The Doctor utilizes their authoritative voice, making it easy for Mundy – who relies on faith instead of fact – to believe them without all the proof.

On top of this, even if the machine did register the Doctor as a Time Lord, it’s nearly impossible that the machine would correctly assess the danger of immolation on the species. The machine would need to have the following:

A comprehensive understanding of the Time Lord's biology

How the Time Lord species differs from humans

An engineering-level understanding of how the Villengard landmine works.

All three of those variables would influence the outcome of immolation of a traditional Time Lord. If any one of these prerequisites isn’t met, the machine would still have questionable accuracy.

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Because of these issues, Mundy Flynn couldn’t have actually known whether the Doctor was lying about what would happen if the landmine went off in Doctor Who’s “Boom.” She probably is just making a judgment call based on the machine telling her that the Doctor isn’t human. Moreover, the Doctor utilizes their authoritative voice, making it easy for Mundy – who relies on faith instead of fact – to believe them without all the proof.

The Doctor Lying Would Continue A Major Theme Of Steven Moffat's Era

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The theory that the Doctor is lying in Doctor Who’s “Boom” seems increasingly likely based on the fact that the episode was written by Steven Moffat. There have always been questions about the Doctor’s honesty, but the Doctor lying became more central to the show during Moffat’s era. In Doctor Who season 5, episode 13, “The Big Bang,” River Song explains that “Rule One: the Doctor lies,” which is also stated on three other occasions.

It fits Moffat’s perception of the Doctor that they would lie to Mundy Flynn in order to save Ruby Sunday

Examples of this within the best Steven Moffat episodes of Doctor Who include the Doctor lying about their own death, lying to their companions about upcoming dangers, and lying about their age. The Eleventh Doctor also lies about both Amys and Rory being able to escape in the TARDIS together, betraying them at the last moment by locking out the older Amy.

In many of those cases, the Doctor’s lies allowed them to save themselves or the people that they love. As such, it fits Moffat’s perception of the Doctor that they would lie to Mundy Flynn in order to save Ruby Sunday – a companion that they related to and bonded with on an emotional level more than almost any before.

Doctor Who Season 14 Already Hinted At Fifteen's Hidden Dark Side

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On top of Moffat increasing the likelihood of the lie, Doctor Who has hinted at a morally ambiguous side of the Fifteenth Doctor. In Doctor Who’s 2023 Christmas special, the Doctor seemed more enthralled by the goblins' song than they were worried about Lulubelle’s safety. Then, in the very first episode of Doctor Who season 14, the Doctor intentionally scares the space babies after Ruby Sunday tries to calm the fears. They only walk back their statements about the Bogeyman after everyone starts crying. This could be an indication that the Fifteenth Doctor has a darker side to them.

However, there is another possible explanation. The Fifteenth Doctor’s character arc heavily relates to their emotions surrounding the fact that they are an orphan, a fact established by Doctor Who’s Timeless Child arc. Both Lulubelle and the space babies were also orphans, giving the Doctor a reason to act differently in those situations than they would otherwise. Ultimately, only time will tell whether the Fifteenth Doctor has a different side in Doctor Who.